Field of the Invention
The invention relates generally to power subsystems for downhole equipment such as electrical submersible pumps (ESP's), and more particularly to means for improving the effectiveness of sealing components in downhole equipment that are exposed to high temperatures and dielectric oils.
Related Art
Downhole equipment such as ESP systems are commonly installed in wells for purposes of producing fluids (e.g., oil) from the wells. Power suitable to drive the equipment is produced at the surface of the wells and is delivered to the equipment via power cables that extend into the wells. The power cables may have one or more electrical junctions, such as splices to motor leads and “pothead” connectors that couple the power cable to the downhole equipment.
The motor of an electric submersible pump is commonly connected to the power cable through a pothead connection. The motor typically has one or more terminals which extend through an insulating block in the motor housing so that a pothead connector can be coupled to the terminals. On the interior of the motor, the terminals are connected to leads which are in turn connected to the windings of the motor.
The interior of the motor is often filled with dielectric oil. This oil has lubricating, cooling and electrically insulating properties. Insulating boots are usually installed around the motor leads at the interior end of the insulating block. These boots provide a seal around the leads and prevent particles which are suspended in the oil from getting between the motor leads and the insulating block. The boots, however, are made of elastomeric materials that typically swell when exposed to the dielectric oil, resulting in gaps between the boots and the motor leads which impairs their functionality.
It would be desirable to provide improved means for manufacturing and installing boot-type seals so that the problems associated with swelling of the elastomeric seals are reduced or avoided.